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212-375

Zurn-Wilkins 212-375 Installation guide

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Installation Testing Maintenance Instructions
INDOOR INSTALLATION
Indoor installation is preferred in areas that
are subject to freezing conditions. All the
basic installation instructions apply to such
installations. CAUTION: An adequately
sized drain is required to prevent pos-
sible water damage due to relief valve
discharge.
OUTDOOR INSTALLATION
The Model 375/475 Series Backow Pre-
venter may be installed outdoors only if the
device is protected against freezing condi-
tions. Exposure to freezing conditions will
result in improper function or damage to the
device. The installation location must be
kept above 32°F. All the basic installation
instructions apply.
PLACING THE DEVICE IN SERVICE
1. Start with both shut-off valves closed.
Slowly open the inlet shut-off valve un-
til the backow preventer is completely
pressurized. A brief discharge from the
relief valve may occur while the device is
pressurizing. The discharge should cease
by the time the shut-off valve is fully open.
If the discharge does not stop, refer to
"MAINTENANCE INSTRUCTIONS" for
repair procedures.
2. After the device has been pressurized,
vent all trapped air by slightly opening
each of the four test cocks.
3. Slowly open the downstream shut-
off valve. The Model 375/475 Series
Backow Preventer is now in service.
4. If spitting or intermittent discharges
from the relief valve are noted, it could
be a result of pressure uctuation and/
or a water hammer condition in the sys-
tem. If such conditions exist, install wa-
ter pressure reducing valves or water
hammer shock arrestors in compliance
with industry standards as needed.
5. After the Model 375/475 Series has
been properly installed, test the device
(see "TEST PROCEDURES"). If the
device fails the test, remove the rst
and second check valves and thor-
oughly ush the device. If the relief
valve fails to operate properly, inspect
the sensing passage for clogging (see
"MAINTENANCE INSTRUCTIONS").
Clean rubber seals of all debris and
place unit back in service.
OUTDOOR INSTALLATION
Model 375ADABGVIC
INDOOR INSTALLATION
Model 375
OUTDOOR INSTALLATION
Model 475 (2 1/2" & 3")
INSTALLATION INSTRUCTIONS
CAUTION: Installation of Backow Preventers must be performed by qualied, licensed
personnel. The installer should be sure the proper device has been selected for the par-
ticular installation. Faulty installation could result in an improperly functioning device.
ZURN WILKINS Model 375/475 Series Assemblies are for use on potable water lines
where a health hazard exists in the event of a backow situation.
Damage to the device could result wherever water hammer and/or water thermal expan-
sion could create excessive line pressure. Where this could occur, shock arrestors, check
valves and/or pressure relief valves should be installed downstream of the device.
If installation is in a pit or vault, the Backow Preventer must never be submerged in
water because this could cause a cross-connection. Make sure that the pit or vault always
remains dry by providing ample drainage. (Consult local codes.)
1. Before installing a Model 375/475 Series Backow Preventer, ush the line thor-
oughly to remove all debris, chips and other foreign matter. If required, a strainer
should be placed upstream of the Backow Preventer. CAUTION: Do not use a
strainer in seldom used emergency waterlines such as re lines.
2. Provide adequate space around the installed unit so that the test cocks will be
accessible for testing and servicing.
3. Install valve at least 12 inches above surrounding ood level.
4. The Model 375 series has been tested and approved in the horizontal position.
Contact factory before installing in other orientations.
5. Always consult local codes for installation methods, approvals and guidance.
PROTECTIVE
ENCLOSURE
DIRECTION OF FLOW
12" MIN.
30" MAX.
®
LEAD-FREE*
AIR GAP
W/DRAIN
DIRECTION OF FLOW
12" MIN.
30" MAX.
12" MIN.
30" MAX.
PROTECTIVE
ENCLOSURE
DIRECTION OF FLOW
(Patent No. 8,997,772)
! WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov
! ADVERTENCIA: Cáncer y daño reproductivo - www.P65Warnings.ca.gov
! AVERTISSEMENT: Cancer et néfastes sur la reproduction - www.P65Warnings.ca.gov
Model 375, 375A (R), 375DA & 375ADA (R)
Reduced Pressure Principle Assembly (2 1/2", 3", 4" & 6")
Reduced Pressure Detector Assembly (2 1/2", 3", 4" & 6")
Model 475 & 475V
Reduced Pressure Principle Assembly (2 1/2" & 3")
*This product contains a weighted average lead content less than 0.25% for wetted surfaces.
Testing Procedures
2
ZURN WILKINS
1747 Commerce Way, Paso Robles, CA 93446 Phone:855-663-9876 Fax:805-238-5766
SPECIFICATIONS
Maximum working water pressure: 175 PSI
Maximum working water temperature: 140°F
Hydrostatic test pressure: 350 PSI
End connections: Flanged ANSI B16.1 Class 125
Grooved AWWA C606
sure reading remains steady then the #2 check valve is re-
ported as "closed tight." Go to Test #3. If the differential
pressure reading falls to the relief valve opening point, bleed
water through the low side bleed needle valve until the
gauge reading reaches a value above the #1 check valve
pressure drop. If the gauge reading settles above the relief
valve opening point, record the #2 check valve as "closed
tight," and proceed to Test #3. If the differential pressure
reading falls to the relief valve opening point again, then the
#2 check valve is noted as "leaking," and Test #3 cannot
be completed. If the differential pressure reading drops, but
stabilizes above the relief valve opening point, the #2 check
valve can still be reported as "closed tight."
Note: Due to disc compression, you may need to bleed off
water through low side bleed needle valve several times be-
fore the gauge reading will settle above relief valve opening
point.
TEST NO.3 - TIGHTNESS OF #1 CHECK VALVE
REQUIREMENT:
The static pressure drop across #1 check valve shall be greater
than the relief valve opening point (test #1), and at least 5.0 psid.
PROCEDURE:
1. With the vent hose connected to test cock #4 as in step 3 of
Test #2, bleed water from the zone through the low side bleed
needle valve on the gauge until the reading exceeds the #1
check valve pressure drop. Close the low side bleed needle valve.
After the gauge reading settles, the steady state differential
pressure reading indicated (reading is not falling on the gauge) is
the actual static (i.e., no ow) pressure drop across check valve
#1 and is to be recorded as such.
2. Close all test cocks, slowly open shutoff valve #2 and remove
equipment.
LOW SIDE HOSE
(GREEN)
LOW SIDE BLEED
NEEDLE VALVE (GREEN)
#1 TEST COCK
#4 TEST COCK
#3 TEST COCK
#2 TEST COCK
#2 SHUT-OFF
VALVE
#1 SHUT-OFF
VALVE
HIGH SIDE BLEED
NEEDLE VALVE (RED)
VENT HOSE
HIGH SIDE HOSE
(RED)
(BLACK)
Capacity thru Schedule 40 Pipe
Pipe size 5 ft/sec 7.5 ft/sec 10 ft/sec 15 ft/sec
2 1/2" 75 112 149 224
3" 115 173 230 346
4" 198 298 397 595
6" 450 675 900 1351
8" 780 1169 1559 2339
10" 1229 1843 2458 3687
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MODEL 375/475 SERIES ASSEMBLY
Equipment Required: Differential pressure gauge test kit.
TEST NO. 1 - RELIEF VALVE OPENING POINT
REQUIREMENT:
The differential pressure relief valve must operate to maintain the
zone between the two check valves at least 2 psi less than the
supply pressure.
PROCEDURE:
1. Flush water through test cocks #1, #2 (open #2 slowly), #3
and #4 by opening and closing each test cock one at a time,
to eliminate foreign material.
2. Install appropriate ttings to test cocks. Attach hose from the
high side of the differential pressure gauge to the #2 test
cock then attach hose from the low side of the gauge to the
#3 test cock. Open test cock #3 slowly and then bleed all air
from the hose and gauge by opening the low side bleed
needle valve.
3. Maintain the low side bleed needle valve in the open posi-
tion while test cock #2 is opened slowly. Open the high side
bleed needle valve to bleed all air from the hose and gauge.
Close the high side bleed needle valve, then close the low
side bleed needle valve after the gauge reading has reached
the upper end of the scale.
4. Close the #2 shut-off valve. If the gauge reading drops to
the ow end of the gauge scale and the differential pressure
relief valve discharges continuously, then the #1 check valve
is leaking.
5. If this occurs, Tests #1, #2 and #3 cannot be completed
(See USC Maintenance Guide). However, should the gauge
reading remain above the differential pressure relief valve
opening point, then observe the gauge reading. This is the
apparent pressure drop across the #1 check valve.
6. Open the high side control needle valve approximately one
turn, and then open the low side control needle valve no
more than 1/4 turn to by-pass water from the #2 test cock to
the #3 test cock. Observe the differential pressure reading
as it slowly drops to the relief valve opening point. Record
this opening point value when the rst discharge of water is
detected. Close the low side needle valve.
TEST NO. 2 - TIGHTNESS OF #2 CHECK VALVE
REQUIREMENT:
The #2 check valve shall be tight against backpressure.
PROCEDURE:
1. Maintain the #2 shut-off valve in the closed position (from
Test #1). Vent all air through the vent hose by opening the
vent needle valve. Close the vent needle valve only (The
high side control needle valve is to remain open).
2. Attach the vent hose from the gauge to the #4 test cock,
then open the #4 test cock. Bleed water from the zone by
opening the low side bleed needle valve on the gauge in
order to re-establish the normal reduced pressure within
the zone. Once the gauge reading reaches a value above
the #1 check valve pressure drop, close the low side bleed
needle valve.
3. Open the vent needle valve. If the indicated differential pres-
#2 RETAINER (4" & 6")
PLASTIC RETAINER(2½"-3")
#2 CHECK ASSEMBLY
#1 RETAINER
GASKET
#1 CHECK ASSEMBLY
SEAT ASSEMBLY
SEAL RING
O-RING (SEAT)
O-RING
SEAL RETAINER
WASHER
NUT
SEAT ASSEMBLY
SEAL RING
O-RING
(BOLT)
SEAL RETAINER
WASHER
BOLT
CHECK HANDLE
O-RING (SEAT)
Maintenance Instructions
3
FIGURE 1
FIGURE 2
FIGURE 3
CHECK ASSEMBLY
(2 ½”- 3”)
375/375DA
(2 ½”- 6”)
375A/375ADA
All Model 375/475 Series Backow Preventers must be inspected
and maintained by licensed personnel at least once a year or
more frequently as specied by local codes. Replacement of
worn or damaged parts must only be made with genuine "ZURN
WILKINS" parts.
GENERAL MAINTENANCE
1. Clean all parts thoroughly with water after disassembly.
2. Carefully inspect rubber seal rings and o-rings for damage.
3. Test unit after reassembly for proper operation (refer to
"TESTING PROCEDURES").
SERVICING RELIEF VALVE
1. Remove relief valve cover bolts and cover. Gently pull on
diaphragm to remove the cartridge assembly.
2. Inspect seal ring for cuts and embedded debris. Turn over or
replace if required.
3. Disassemble cartridge by unscrewing relief valve retaining
screw.
4. Inspect diaphragm and o-rings for damage. Replace re-
quired parts and apply a light coat of lubricant to plunger
o-ring.
5. Carefully reassemble cartridge assembly. Tighten retainer
screw to 13 -17 in/lbs.
6. Inspect relief valve seat for wear on seating surface. If damaged,
replace seat and seat o-ring. Install spring over seat guides.
7. Insert cartridge assembly into relief valve body.
8. Replace relief valve cover and cover bolts.
9. Place the device in service and test per "TESTING PROCE-
DURES" on page 2.
NOTE: Disassembly of the seat assembly is not recommended.
If the seat assembly needs repair, please contact factory.
RELIEF VALVE ASSEMBLY
SERVICING CHECK VALVES
1. Close the outlet and then the inlet shut-off valves.
2. Open No. 2, 3 and 4 test cocks to release internal pressure.
Leave them open during check removal and reinstallation.
3. Loosen and remove the two nuts, bolts and seal from the
grooved coupling around the access cover.
4. If the valve has a wire retainer on the #1 check assembly,
pinch together the exposed ends, pull toward the #2 check
and remove from valve.
5. If the valve has a plastic retainer on the #1 check, grasp
one of the exposed ends, push down and then pull toward the
#2 check. The retainer should “spiral” out of the groove
around the check.
6. (2-1/2 – 3” 375/375DA Models) Remove the #2 retainer and
check in the same manner as the #1.
7. (4 – 6” 375A/375ADA Models) Remove the #2 check by lo-
cating one of the two spring-loaded plate retainers around
the face of the check. Pinch the sides of the spring together
and rotate the plates out of the body groove one at a time.
Remove the 2nd retainer the same way.
8. Always service the checks one at a time to avoid mixing
parts. Start by removing the hardware and o-rings from the
back of the check assembly (See “Check Assembly” illustra-
tion). Separate the seal retainer from the assembly to expose
the seal ring.
9. Inspect the seal ring for cuts or embedded debris. If the
reverse side of the seal is unused, the seal ring can be invert-
ed and used temporarily until a new seal is obtained. Inspect
seat o-ring and replace if cut or damaged in any way.
Inspect valve cavity and seating areas. Flush with water to
remove any debris.
10. (Reassembly, 2-1/2 – 3” 375/375DA Models) Lubricate the
#2 check o-ring, install in the body and close the #4 test cock
to hold it in place. Install the plastic retainer by inserting one
end into the body groove and then sliding your hand around
the face of the retainer, pushing it into the groove as you go.
The retainer will “snap” into place when fully seated. Install #1
check and retainer in the same way.
11. (Reassembly, 4 – 6” 375A/375ADA Models) Lubricate the #2
check o-ring, install in the body and close the #4 test cock. In-
stall the #2 check retainers into the body groove one plate at
a time, squeezing the spring ends together to clear the stops
on the face of the seat. Lubricate and install the #1 check,
close the #2 test cock and install:
(A) wire retainer by pinching the ends together, placing the
lower edge of the ring into the body groove below the check
and rotating the top of the ring into the notch above the check.
(B) plastic retainer as described above in the 2-1/2 – 3” 375/
375DA Models Reassembly section.
12. Lubricate the outside surface of the grooved coupling gasket.
Reassemble access cover and grooved coupling, making
sure the ends of the coupling touch each other. Close any
remaining open test cocks and place valve back in service.
COVER
BOLTS
COVER
UPPER
PLUNGER
DIAPHRAGM
PLUNGER
O-RING
LOWER
PLUNGER
SEAL
RING
WASHER
RETAINER
SCREW
SEAT
SPRING
SEAT
O-RING
BODY
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MODEL 375ADA 2-1/2", 3", 4" & 6" (STANDARD AND METRIC)
0
5
10
15
20
0 200 400 600 800 1000 1200
FLOW RATES (GPM)
PRESSURE LOSS (PSIG)
0
35
69
104
0.0 12.6 25.2 37.9 50.5 63.1 75.7
FLOW RATES (l/s )
PRESSURE LOSS (kpa)
MODEL 375DA 2 1/2", 3" & 4" (STANDARD & METRIC)
0
5
10
15
20
0 200 400 600 800
PRESSURE LOSS (PSIG)
0
34
69
103
138
0.0 12.6 25.2 37.9 50.5
FLOW RATES (l/s )
PRESSURE LOSS (kpa)
MODEL 375 6", 8" & 10" (STANDARD & METRIC)
0
5
10
15
20
0 1000 2000 3000 4000
FLOW RATES (GPM)
PRESSURE LOSS (PSIG)
0
35
69
104
138
0.0 63.1 126.2 189.3 252.4
FLOW RATES (l/s )
PRESSURE LOSS (kpa)
MODEL 375A 2-1/2", 3", 4" & 6" (STANDARD AND METRIC)
0
5
10
15
20
0 200 400 600 800 1000 1200
FLOW RATES (GPM)
PRESSURE LOSS (PSIG)
0
35
69
104
138
0.0 12.6 25.2 37.9 50.5 63.1 75.7
FLOW RATES (l/s )
PRESSURE LOSS (kpa)
IS375 (REV. E 6/17)
4
Proper performance is dependent upon licensed, qualied personnel performing regular, periodic testing according to ZURN WILKINS' specications and
prevailing governmental & industry standards and codes and upon following these installation instructions. Failure to do so releases ZURN WILKINS of
any liability
that it might otherwise have with respect to that device. Such failure could also result in an improperly functioning device.
See spec sheet BF-475&V212-3 for ow curves
SIZE MODEL MODEL 375 RELIEF RUBBER ONLY MODEL 375 RELIEF COMPLETE MODEL 375 CHECKS ONLY
2 1/2" - 3" 375/375DA RK212-375R RK212-375 RK212-350
4" 375/375DA RK212-375R RK212-375 RK4-350
6" 375/375DA RK212-375R RK212-375 RK6-350
2 1/2" - 4" 375A/375ADA RK212-375R RK212-375 RK4-350
6" 375A/375ADA RK212-375R RK212-375 RK6-350
PROBLEM POSSIBLE CAUSES CORRECTIVE ACTION
1. SUDDEN OR RAPID 1. Drop in inlet pressure. 1. Install an in-line spring loaded check valve or pressure reducing
SPITTING 2. Sudden increase in downstream pressure valve upstream of Backow Preventer.
due to waterhammer from quick closing 2. Install an in-line spring loaded check valve or pressure reducing
shut-off valve installed downstream. valve downstream of Backow Preventer.
2. LIGHT INTERMITTENT 1. Slightly fouled #1 check. 1. Clean #1 check and/or turn check valve seal ring over or replace.
DRIP 2. Slightly fouled relief valve seat. 2. Clean relief valve seat and/or turn relief valve seal ring over or replace.
3. CONTINUOS 1. Fouled #1 check and/or #2 check. 1. Clean check valves and/or turn check valve seal ring over or replace.
DISCHARGE 2. Fouled relief valve seat. 2. Clean relief valve seat and/or turn relief valve seal ring over or replace.
Troubleshooting
Repair Kits
Performance Characteristics
MODEL 375DA 6", 8" & 10" (STANDARD & METRIC)
0
5
10
15
20
0 1000 2000 3000 4000
PRESSURE LOSS (PSIG)
0
34
69
103
138
0.0 63.1 126.2 189.3 252.4
FLOW RATES (l/s )
PRESSURE LOSS (kpa)
MODEL 375 2 1/2", 3" & 4" (STANDARD & METRIC)
0
5
10
15
20
0 200 400 600 800
FLOW RATES (GPM)
PRESSURE LOSS (PSIG)
0
35
69
104
138
0.0 12.6 25.2 37.9 50.5
FLOW RATES (l/s)
PRESSURE LOSS (kpa)
⃟
Rated Flow (Established by approval agencies)
10" (250mm)
21/2" (65mm)
6" (150mm)
3" (80mm)
8" (200mm)
6" (150mm)
8" (200mm)
10" (250mm)
4" (100mm)
6" (150mm)
21/2" (65mm)
3" (80mm)
4" (100mm)
6" (150mm)
21/2" (65mm)
3" (80mm)
4" (100mm)
21/2" (65mm)
3" (80mm) 4" (100mm)
ZURN WILKINS
1747 Commerce Way, Paso Robles, CA 93446 Phone:855-663-9876 Fax:805-238-5766
www.zurn.com
®
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